[Android] Add test for csp support.

The test set the manifest field script-src with 'self' or
'unsafe-inline' values to disallow/allow change page titles
with the diferent csp settings.

For embedded client test:
1. install XWalkRuntimeClientEmbeddedShell.apk
2. python build/android/test_runner.py instrumentation \
--test-apk=XWalkRuntimeClientEmbeddedTest -v -f \
testCsp

For shared client test:
1. install XWalkRuntimeLib.apk
2. install XWalkRuntimeClientShell.apk
3. python build/android/test_runner.py instrumentation \
--test-apk=XWalkRuntimeClientTest -v -f testCsp